Rounding the dirt track at the Gentilly Stage one afternoon, Sophie spies people streaming in and out, and demands to use one.

“It’s beautiful!” she gasps as we approach the row of aquamarine plastic. Her face is full of wonder, as if gazing upon the monolith in “2001: A Space Odyssey.”

Photo by Mary SperaSophie rocks to the Imagination Movers at the 2010 New Orleans Jazz Fest...The illusion is shattered the instant she peeks down the hole inside. She is horrified to discover she is not the day’s first, or only, customer -- and that port-a-potties don’t flush.

And the afternoon sun, coupled with a port-a-potty’s inherent lack of ventilation, makes for a most unpleasant environment. “I’m sweaty, Daddy,” she complains.

But I feel it is important to see our mission through. After balancing her on a half-inch thick protective layer of toilet paper, we make our escape and bathe in hand sanitizer.

She does not ask to use a port-a-potty again.

Instead, when nature calls, she and her buddy Gwendolyn deploy their own personal-size, portable potties, right there on our blanket under the oak tree at the back of the Gentilly Stage field.

Seated side-by-side, their shorts around their ankles, they discuss the day’s events and review the finer points of Wayne Toups’ set. When finished, they are cheered as enthusiastically as Marcia Ball.

Public toilet adventures aside, it was a good festival for the offspring. Not quite three years old, Sophie is a veteran of three Jazz Fests. Her newly minted brother is following in her footsteps.

Sam braved the Fair Grounds twice this year. He treats Jazz Fest like most destinations where he finds himself these days: As a place to sleep between feedings.

Plopped on a blanket in the shade, he models his sister’s noise-reducing headphones. The headphones are hot pink. He looks like a deejay at a nursery nightclub: It’s Sam Spera on the wheels of steel!

To his big sister, the Imagination Movers are the Beatles. Up on my shoulders, she bounces in time to the beat and waves her little hands in the air like she just don’t care.

When I turn away from the stage, she yanks my hair like a bridle. No horse has ever known such pain.

Keith Spera / The Times-Picayune...while baby brother Sam makes a friend.Back at the blanket, she is hopped up on Crawfish Monica, fried crawfish tails and nectar cream snoballs. She and her sidekick Serena stage their own dance party. Sophie segues from the OktoberFest “Chicken Dance” to a bent-at-the-waist, hand-on-the-ground move you might see in a Lil Wayne video.

She is her father’s daughter.

All dancing ceases when a most unlucky ladybug lands on the blanket. No musician at Jazz Fest – not Jeff Beck, not Pearl Jam, not B.B. King – can compete with a live ladybug for the attention of two-year-olds.

Sam, meanwhile, has seduced a gaggle of young women. Lovely, professional, mostly single and without children of their own, they are friends from New York, Los Angeles and multiple points in between who travel to Jazz Fest each year to let their hair down.

Way down.

As the sun sets on Jazz Fest, Sam basks as the object of their affection. They dub him Sam-tastic. He is passed around, cradled to various bosoms, cooed and wooed with no expectation of anything in return.

Is it normal for a father to be jealous of his infant son?

If Sam and I could time-travel 20 years into the future, I would impart on him the following insight with which to return to the present:

Son, you will never have it better than you do right now.

Keith Spera can be reached at kspera@timespicayune.com or 504.826.3470. Read more of 'The Paternity Test.'